The present invention relates to a boron-containing compound, a polymerizable composition and an ion-conductive polyelectrolyte which are for electro-chemical devices.
As an electrolyte that constitutes an electro-chemical device such as a battery, capacitor, sensor or the like, a liquid electrolyte has been used from the viewpoint of ion-conductive properties. The liquid electrolyte, however, has been disadvantageous, for example, in that its leakage tends to damage an apparatus.
On the other hand, secondary batteries using a solid electrolyte such as an inorganic crystalline material, inorganic glass, organic polymer or the like have recently been proposed. As compared with the employment of a conventional liquid electrolyte obtained by the use of a carbonate solvent, the employment of the solid electrolyte is free from the leakage of the carbonate solvent and permits reduction of the ignitability of the electrolyte, so that it improves the reliability and safety of a device.
Organic polymers are expected to be developed, for example, because in general, they are excellent in processability and moldability, give an electrolyte having flexibility and processability in bending, and improve the degree of freedom of design of a device obtained by the use of the organic polymer.
The organic polymers described above, however, are inferior to other materials in ion-conductive properties. There is widely known, for example, an attempt to use a material obtained by incorporating a poly(ethylene oxide) with a specific alkali metal salt, as a polyelectrolyte (for instance, JP-A-2002-158039).
JP-A-2001-72877 discloses a copolymer of a boron-containing polymerizable monomer and another polymerizable monomer. This polymer is an ion-conductive material capable of improving the transference number of charge carriers, and the above reference discloses a polyelectrolyte and an electrochemical device which are obtained by the use of said polymer.
However, even when the polyelectrolyte concretely described in the above reference is used, no ionic conductivity value required, in practice, of an electrolyte for a lithium ion secondary battery is obtained.